Experimental Study of Heat Transfer and Fluid Flow Inside a Differentially Heated Closed Rectangular Cavity Using Two Non-Invasive Techniques

Buoyancy-induced flow in closed cavities is subject of interest since last few decades because of its complexity and a wide range of applications in different areas. To understand such types of phenomena, experiments are performed in the differentially heated vertical closed rectangular cavity for air (Pr=0.71). Temperature potential has been applied across the two vertical walls of the cavity while other two walls have been kept insulated. The aspect ratio of the cavity (height to width ratio) is kept as 3. Experiments are done using two non-invasive techniques, namely, Mach Zehnder Interferometer (MZI) and smoke visualization. MZI and smoke visualization techniques are used to get two-dimensional full field temperature profiles and streaklines of the flow inside the cavity. Experiments are performed for different Rayleigh numbers. Results obtained through two experiments techniques also have been compared with numerical results (performed using COMSOL). Thermal and hydraulic boundary layer formation near the vertical walls has been observed from the results of MZI and smoke visualization respectively. The dominance of corner flow has been observed where the maximum heat transfer takes place while in the core of the cavity, the weak convective heat transfer has been seen.